00:00It doesn't look like it, but these are troubled waters.
00:12Just below the surface, a small spiny creature is wreaking havoc.
00:19These barren areas are quite striking in that they really aren't barren, there's not a lot
00:22growing there.
00:23They're kind of devoid of the typical healthy marine life that you'd expect to find.
00:28Sea urchins are eating their way through the golden kelp forests here in Victoria's Port
00:33Phillip Bay.
00:38Researchers from the University of Melbourne are out counting urchins.
00:42So we swim out to see how they're going.
00:45The highest today was 20 per square metre.
00:48In a healthy kelp forest, you'll find about four urchins per square metre.
00:53They estimate there's about 130 million of these urchins currently in Port Phillip Bay.
00:59A big issue was increased nutrients being pumped into the bay in things like waste water,
01:05which provided extra food.
01:08When the water in the bay was cleaned up, the excess urchins went in search of something
01:13else to eat and started demolishing the kelp.
01:16You change the balance in the natural system and then, you know, things get out of balance.
01:23In a bid to restore balance, the team, led by the Nature Conservancy, has been growing
01:28kelp in a lab and then planting it here.
01:30What are you marking out here, Scott?
01:33We're going to mark the two ends of our plots, they're about 50 metres by 20 metres in size.
01:37We'll mark the two ends of those and we're going to jump in the water and see all the
01:40kelp that's grown.
01:42This kelp was planted a bit under a year ago.
01:47In the first two years of the project, the team has planted 400,000 baby kelp, many of
01:55them here in this restoration area.
01:57And you can already see many of these kelp are taking and growing in this area and replenishing
02:04what was once an urchin barren.
02:06The couple of months since you've planted that, how much has it grown?
02:09Yeah, so when we plant these out, they're about up to five millimetres in size, so they're
02:13pretty little, we can just see them with our eyes.
02:16And we see some pretty rapid growth, it's quite a satisfying species to watch.
02:20Elsewhere in the bay, some healthy kelp forests remain.
02:28So this is the goal?
02:30That's right, yeah, so what we're looking at here is a healthy kelp forest.
02:35It's not just kelp that's thriving, it's other seaweed species and marine life.
02:40Lots of fish and crabs and crustaceans and abalone and all these things really rely on
02:44those kelp forests to be there in order to survive.
02:47So it's important for that, they provide a really good benefit in terms of being able
02:50to protect our shorelines, they improve our water quality.
02:54The Victorian Government has just given $300,000 to keep the project going for the next three
03:00years.
03:01But the team says more funding will be needed long term.
03:04Because we really want some big bold commitments to help us really take this to scale.
03:09And hopefully restore some underwater forests.
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